” Do you feel in control? ” : Towards Novel Approaches to Characterise, Manipulate and Measure the Sense of Agency in Virtual Environments
IEEE Trans. Visual. Comput. Graphics. 2018-04-01; 24(4): 1486-1495
DOI: 10.1109/TVCG.2018.2794598
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While the Sense of Agency (SoA) has so far been predominantly characterised in VR
as a component of the Sense of Embodiment, other communities (e.g., in psychology
or neurosciences) have investigated the SoA from a different perspective
proposing complementary theories. Yet, despite the acknowledged potential
benefits of catching up with these theories a gap remains. This paper first aims
to contribute to fill this gap by introducing a theory according to which the SoA
can be divided into two components, the feeling and the judgment of agency, and
relies on three principles, namely the principles of priority, exclusivity and
consistency. We argue that this theory could provide insights on the factors
influencing the SoA in VR systems. Second, we propose novel approaches to
manipulate the SoA in controlled VR experiments (based on these three principles)
as well as to measure the SoA, and more specifically its two components based on
neurophysiological markers, using ElectroEncephaloGraphy (EEG). We claim that
these approaches would enable us to deepen our understanding of the SoA in VR
contexts. Finally, we validate these approaches in an experiment. Our results
(N=24) suggest that our approach was successful in manipulating the SoA as the
modulation of each of the three principles induced significant decreases of the
SoA (measured using questionnaires). In addition, we recorded participants’ EEG
signals during the VR experiment, and neurophysiological markers of the SoA,
potentially reflecting the feeling and judgment of agency specifically, were
revealed. Our results also suggest that users’ profile, more precisely their
Locus of Control (LoC), influences their level of immersion and SoA.